Conventional slider-zipper assemblies typically comprise a plastic zipper having two interlocking profiles and a slider for opening and closing the zipper. In one type of slider-zipper assembly, the slider straddles the zipper and has a separating finger at one end that is inserted between the profiles to force them apart as the slider is moved along the zipper in an opening direction. The other end of the slider is sufficiently narrow to force the profiles into engagement and close the zipper when the slider is moved along the zipper in a closing direction.
Another type of slider-zipper assembly avoids the use of a separating finger. For example, U.S. Pat. No. 6,047,450 discloses a zipper comprising a pair of mutually interlockable profiled structures. The first profiled structure comprises an interlocking member on a surface directed toward the second profiled structure and an integral base directed away from the second profiled structure. Likewise, the second profiled structure comprises an interlocking member on a surface directed toward the first profiled structure and an integral base directed away from the first profiled structure. Additionally, portions of the two profiled structures form a fulcrum about which the profiled structures may be pivoted out of engagement when lower edges of the bases are forced towards each other. As oriented on a bag having the zipper at the top, the slider has a top from which two arms depend. The slider straddles the zipper and has a closing end and an opening end. The opening end is narrower than the closing end. Additionally, the slider does not have a separating finger. Rather, the zipper is opened by pivoting the interlocked profiled structures out of engagement about the fulcrum. The slider arms are shaped at the opening end to achieve this action by forcing the lower edges of the bases towards each other.
It is known to use slider-operated zippers in reclosable packaging for perishable foodstuffs. It is desirable that such packaging be provided with means for preventing the inadvertent or unwelcome opening of the package or bag while inside a store. While a slider facilitates a consumer opening and reclosing the package and hence is desirable in some instances, the slider makes it difficult for the manufacturer to employ conventional techniques to render the package tamper evident. There is a need for a tamper-evident seal designed to reveal when a reclosable package or bag with slider-operated zipper has been opened prior to purchase.